How Al-Shabaab picks its targets

By Peter Bergen, CNN National Security Analyst

Updated 1613 GMT (2313 HKT) September 23, 2013

Photos: Kenya mall attack51 photos

Kenya mall attack – Relatives of Johnny Mutinda Musango, 48, weep after identifying his body at the city morgue in Nairobi, Kenya, on Tuesday, September 24. Musango was one of the victims of the Westgate Mall hostage siege. Kenyan security forces were still combing the mall on the fourth day of the siege by al Qaeda-linked terrorists.

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Kenya mall attack – Ann Gakii reacts at the Nairobi City Mortuary after identifying the body of her father, who was killed in the mall attack on Saturday.

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Kenya mall attack – A Kenyan soldier runs through a corridor on an upper floor at the Westgate Shopping Mall in Nairobi, Kenya, on September 24, shortly before an explosion was heard. Sounds of heavy gunfire erupted from the mall Tuesday, even as authorities said they had the building under their control. But four days after Al-Shabaab terrorists stormed the swanky mall, several gunmen -- including snipers -- were still inside, two senior officials said.

Kenya mall attack – A woman shields a baby as a soldier stands guard inside the Westgate Mall on Saturday, September 21.

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Kenya mall attack – A rescue worker helps a child outside the mall.

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Kenya mall attack – People who had been hiding inside the mall during the gunfire flee the scene.

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Kenya mall attack – An armed official takes a shooting position inside the mall.

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Kenya mall attack – An armed official crouches on September 21.

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Kenya mall attack – Bodies lie on the ground inside the mall.

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Kenya mall attack – Men help a wounded woman outside the mall.

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Kenya mall attack – Officials carry an injured man in the mall.

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Kenya mall attack – Soldiers move up stairs inside the Westgate Mall.

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Kenya mall attack – Armed police leave after entering the mall. At least one suspect has been killed, a government official said. Police have said another suspected gunman has been detained at a Nairobi hospital.

Kenya mall attack – A woman who had been hiding during the attack runs for cover after armed police enter the mall.

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Kenya mall attack – A body is seen on the floor inside the smoke-filled four-story mall.

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Kenya mall attack – An injured person is helped on arrival at the Aga Khan Hospital in Nairobi after the attack at the upscale mall.

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Kenya mall attack – A soldier directs people up a stairway inside the Westgate on September 21.

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Kenya mall attack – An injured man is wheeled into the Aga Khan Hospital in Nairobi.

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Kenya mall attack – People run from the Westgate Mall.

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Kenya mall attack – A Kenyan woman is helped to safety after the masked gunmen stormed the upscale mall and sprayed gunfire on shoppers and staff.

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Kenya mall attack – Crowds gather outside the upscale shopping mall. The interior ministry urges Kenyans to keep off the roads near the mall so police can ensure everyone inside has been evacuated to safety.

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Kenya mall attack – A policeman carries a baby to safety. Authorities said multiple shooters were at the scene.

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Kenya mall attack – Bodies lie outside the shopping mall.

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Kenya mall attack – A security officer helps a wounded woman outside.

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Kenya mall attack – Elaine Dang of San Diego is helped to safety after the attack. The military asked local media not to televise anything live because the gunmen are watching the screens in the mall.

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Kenya mall attack – Paramedics treat an injured man outside the mall.

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Kenya mall attack – Medical personnel carry a body away.

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Kenya mall attack – A body lies outside the mall. Gunmen shot people outside the mall as they entered it

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Kenya mall attack – A woman is pulled by a shopping cart to an ambulance.

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Kenya mall attack – A wounded man is escorted outside the mall.

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Kenya mall attack – A police officer carries a baby as people keep low and run to safety. Crowds dashed down the streets as soldiers in military fatigues, guns cocked, crawled under cars to get closer to the mall.

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Kenya mall attack – People run away from the scene.

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Kenya mall attack – Armed Kenyan forces take position to secure the area around the shopping mall as ambulances move in to carry the injured.

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Kenya mall attack – A woman reacts after she is rescued from the mall.

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Kenya mall attack – A couple flee the area. As night fell, authorities said they had cornered the gunmen in the mall.

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Story highlights

For Al-Shabaab, the mall was an attractive target because Westerners frequented it

Also, it fits with the Somalia-based terrorist group's enmity with Kenya

The group has recruited around 40 American men and also dozens from Europe

The attack on the Nairobi mall may be an attempt by Al-Shabaab to signal its continued relevance

Al-Shabaab, al-Qaeda's brutal Somali affiliate, has claimed credit for the attack by multiple gunmen at an upscale shopping mall in Nairobi, Kenya that has already killed at least 59 people.

This should not be a surprise. For Al-Shabaab, the mall was an attractive target because Westerners, including Americans, frequented it. The mall is also in the capital of Kenya, a country that Al-Shabaab has good reason to dislike, as the Kenyan military played a major role in handing their forces a defeat last year when they liberated the key Somali port of Kismayo from their control.

Al-Shabaab ("the Youth") tweeted Saturday that "all Muslims inside #Westgate" -- referring to the mall that was attacked in Nairobi -- "were escorted out by the Mujahideen before" the armed assault commenced.

Members of Al-Shabaab use Twitter frequently to communicate their messages to the world. The group has recruited around 40 young American men and also dozens from Europe and has shown that it is comfortable with Internet technology, despite the fact that Somalia is one of the poorest and most anarchic countries on the planet.

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Terrorists attack mall in Kenya

Saturday's attack on the Nairobi mall seems to owe some of its tactics to Lashkar-e-Taiba, the Pakistani terrorist group that attacked upscale hotels catering to Westerners in Mumbai, India, in November 2008 over the course of more than three days, killing 166 people.

In both the Nairobi and Mumbai attacks, a group of armed gunmen shot at civilians indiscriminately and conducted the operation in a manner that would guarantee sustained media coverage over many hours and even days by taking a large number of hostages. In both assaults, the gunmen did not negotiate for the release of hostages but went into the operation seemingly prepared for a fight to the death.

Al-Shabaab has previously shown that it is capable of carrying out operations outside of Somalia, bombing two groups of fans watching the World Cup on television in Kampala, Uganda, on July 11, 2010, killing more than 70. The group seemed to have carried out that operation because Uganda had provided troops to a United Nations-authorized African Union mission then fighting Al-Shabaab in Somalia.

The group has also shown an interest in targets in the West. Eight months before the attack in Uganda, a 28-year-old Somali man armed with a knife and an ax had forced himself into the home of Kurt Westergaard -- a Danish cartoonist who had depicted the Prophet Mohammed with a bomb in his turban -- and tried unsuccessfully to break into the panic room where Westergaard was hiding. Danish intelligence officials said the suspect had links with Al-Shabaab.

Al-Shabaab has managed to plant al-Qaeda-like ideas into the heads of even its American recruits.

Shirwa Ahmed, an ethnic Somali, graduated from high school in Minneapolis in 2003, then worked pushing passengers in wheelchairs at the Minneapolis airport. During this period Ahmed was radicalized; the exact mechanisms of that radicalization are still murky, but in late 2007 he traveled to Somalia.

About a year later, on October 29, 2008, Ahmed drove a truck loaded with explosives toward a government compound in Puntland, northern Somalia, blowing himself up and killing about 20 people, including United Nations peacekeeping troops and international humanitarian assistance workers. The FBI matched Ahmed's finger, recovered at the scene, to fingerprints already on file for him. Ahmed was the first American terrorist suicide attacker anywhere.

Al-Shabaab breaks new ground with complex Nairobi attack

The attack on the Nairobi mall may be an attempt by Al-Shabaab to signal its continued relevance. Over the past three years, Al-Shabaab has lost substantial territory and influence in Somalia. Al-Shabaab controlled much of southern Somalia in 2010, but operations by African Union and Kenyan forces have ended its domination of southern Somalia.

In 2011, the U.N.-sanctioned African Union mission partnered with Somali troops to fight Al-Shabaab militants, and in August of that year, African Union and Somali government forces defeated Al-Shabaab forces in Mogadishu, forcing the militants from a stronghold they had controlled since 2009.

Although Al-Shabaab has long been regarded as a regional offshoot of al-Qaeda, its leaders only declared their formal ties to the international terror organization in February 2012.

While the group seems to have been interested in an alliance before then, in 2010, bin Laden instructed the group's leaders to keep their association with al-Qaeda a secret, fearing that openly linking the groups would be bad for Al-Shabaab's fundraising efforts.

By February 2012, however, bin Laden was dead and Al-Shabaab had suffered significant losses in its southern Somali safe haven.

Al-Qaeda's new leader, Ayman al-Zawahiri, who had earlier petitioned bin Laden to reconsider his views about the proposed merger between Al-Shabaab and al-Qaeda, believed the time was right to announce formal ties between the two groups.

While there are a number of American citizens fighting for a variety of al-Qaeda-affiliated or -inspired organizations, Al-Shabaab seems to boast the most American fighters. According to a 2011 report by the House Committee on Homeland Security, an estimated 40 Americans have joined Al-Shabaab in the last few years, at least 24 of them coming from the Somali community in Minnesota.

Al-Shabaab has prominently featured these recruits in its propaganda operations, releasing three official videos that starred Abu Mansoor al-Amriki ("the father of Mansoor, the American"), who is actually Omar Hammami, in his late 20s from Alabama, who was raised as a Baptist and converted to Islam in high school.

One of the videos shows Hammami preparing an ambush and features English rap lyrics extolling jihad.

Hammami was reported to have been killed on September 12 during the course of some kind of an internal conflict within the Al-Shabaab group.

The news of his death was confirmed on Hammami's Twitter account four days later.